Comminuting machine



Nov. 19, 1963 H. BUSCHMAN cowmuuuwmc MACHINE 3 Sheets-Sheet 1 Filed001.. 4, 1960 INVENTOR WA T/44M H. .Pz/sc/m MN ATTORNEY Nov. 19, 1963 N.H. BUSCHMAN 3,111,278

COMMINUTING MACHINE 3 Sheets-Sheet 2 Filed Oct. 4, 1960 i I] l T l m IINVENTOR ATTORNEY United States Patent 3,111,278 C(PMMINUTING MACHINENathan H. Buschman, Jackson Heights, N.Y. Buschmau Products, Inc, 114 E.4tlth St, New York, N.Y.) Filed Oct. 4, 19%, er. No. 60,489 7 Claims.(Cl. 241257) The present invention relates generally to an improvedcomminuting and dispersing apparatus, and in particular it relates to animproved apparatus for reducing the particle size of a fluid-borne orfluidized material and for uniformly and homogeneously dispersing thefinely comminuted solid phase in the liquid phase.

In the production of stable and uniform dispersions of a finely dividedsolid phase in a liquid phase, such as emulsions, suspensions anddispersions, many types of apparatus and many different procedures havebeen employed. Particle size reduction has been achieved byinterparticle attrition, shear, impact, sonic and ultrasonic mechanicalenergy, and by other means, and the reduced particles are dispersed inthe liquid phase by the violent and intimate dispersion of the particlestherein. While there are many machines available for efiecting particlesize reduction of one or more of the above modes of operation and fordispersing the particles in the liquid phase, these machines possessnumerous drawbacks and disadvantages. They are relatively low capacitymachines requiring high power drive motors, and are generally highlyinefiicient and wasteful of energy. Moreover, they are inflexible and oflimited application, the specific machine being useful with productshaving a very limited range of physical properties. Furthermore, theconventional machines are usually expensive for their rated capacity,reduce the solid phase to a particle size which is either coarse ornon-uniform and of a large range of particle size distribution, arehighly sensitive and sub- 'ject to frequent malfunctioning, andotherwise leave much to be desired.

It is, therefore, a principal object of the present invention to providean improved cornrninuting apparatus.

Another object of the present invention is to provide an improvedapparatus for comrninuting a liquid-borne solid material.

Still another object of the present invention is to provide an improvedapparatus for reducing the particle size of a fluid-borne material andfor uniformly and homogeneously dispersing the finely comrninutedmaterial in the liquid.

A further object of the present invention is to provide an improvedcomminuting and homogenizing apparatus capable of treating a wide rangeof materials in which the liquid phase and solid phase may possesswidely ranging physical properties and characteristics.

Still a further object of the present invention is to provide animproved highly efiicient comminuting and homogenizing apparatus whichpossesses a high capacity relative to its size and consumes a minimum ofenergy.

A further object of the present invention is to provide an apparatus ofthe above nature characterized by its simplicity of structure andoperation, ruggedness, versatility and relatively low cost;

The above and other objects of the present invention will becomeapparent from a reading of the following description, taken inconjunction with the accompanying drawings, wherein FIGURE 1 is afront'elevational view of an improved apparatus embodying the presentinvention, shown partially in section and partially broken away;

FIGURE 2 is an enlarged detail sectional view, taken along line 2-2 onFIGURE 1;

3,111,278 Patented Nov. 19, 1963 FIGURE 3 is a vertical transversesectional view, taken along line 3-3 on FIGURE 2;

FIGURE 4 is an enlarged detail of the connection between the rotor andstator;

1 FIGURE 5 is a sectional view taken along line 55 on FIGURE 3;

FIGURE 6 is a sectional view taken along line 6-6 on FIGURE 3; and

FIGURE 7 is a sectional view taken along line 7--7 on FIGURE 3.

In a sense, the present invention contemplates the provision of animproved comminuting apparatus comprising a pair of relatively movablemembers having confronting surfaces delineating a comminuting Zone,means directing a fluid through said comminuting zone, and a pluralityof vibrating elements disposed in said comminuting zone.

It has been discovered that the presence of the vibrating elementsradically improves the efliciency of the comminuting and dispersingactions of the apparatus, and greatly reduces the particle size of thesolid material thereby to improve the stability and homogeneity of theresulting dispersion.

According to a preferred form of the present invention, there isprovided a stator member having an inner surface of revolution includinga first main upper conical section of relatively small vertex angle, asecond flat annular intermediate section, anda third conical section ofgreater vertex angle than the first section, said inner surfaces havinglongitudinal grooves formed therein along the three sections thereof,the grooves delineating intervening teeth or ribs. A rotor membercoaxially registers with the stator and is provided with outer surfacesconfronting and corresponding with the stator inner surfaces, the bottomand intermediate sections of the rotor surface and the upper part of therotor top main section having longitudinal ribs and grooves formedtherein of a different number than those formed in the stator. The loweror core part of the rotor main section is inwardly offset, and aplurality of tines depend from the upper part of the rotor main sectionand are free at their lower ends and spaced from each other and from thestator face and core face so as to vibrate in response to certainstimuli. The stator is mounted in the open end of a casing on which therotor is mounted and is longitudinally adjustable therein. An impelleris carried by the rotor at the bottom thereof and with the casingdefines a pump for promoting the flow of material through the apparatus.

Referring now to the drawings, which illustrate'a preferred embodimentof the present invention, reference numenal lil generally designates theimproved apparatus or mill which is mounted on a motor-carrying pedestaland is provided with a feed' hopper 12; The pedestal includes acentrally apertured platform 13 provided'with a depending motor mountingplate 14 which terminates at a suitably connected'base plate 16.Centrally located on platform 13 is a support member 17 including ahollow vertical column 18 having upper and lower peripheral flanges 19and 2d, the lower flange 29 having a depending boss registering with acorresponding recess in platform 13 and being bolted thereto. A pair ofaligned suitable bearing members 21 are tightly nested in correspondingenlarged bore sections in opposite ends of column 18.

Mill 10 includes a base member 22 having a circular bottom wall 23 andan upstanding peripheral wall 24, base member 22 being suitably securedto flange I9. Formed in base bottom Wall 23 is a circularaperture-coaxial with column 18 having its upper peripheral bordersurrounded by a collar 26 integrally formedwith Wall 23wand h-aving aconical outer face. The upper section of inner face of wall 22 isthreaded, and has a peripheral shoulder extending to a short verticalwall section 27 which terminates in a second shoulder 28 extending tothe upper edge of an involute face 29 which delineates the wall of acentrifugal pump. A discharge pipe 38 communicates with the interior ofthe lower section of base 22 at the widest point of the involute.

The stator member 30 of mill consists of an integrally formed lowercylindrical portion 32 and an upstanding coaxial upper cylindricalportion 33, of lesser diameter. The intermediate outer surface of thestator lower portion 32 is threaded as at 34 and engages the threadedface of base wall 24 thereby to effect interconnection between base 22and stator and permit relative longitudinal adjustment therebetween. Thelower border of stator portion 32 is inwardly offset and provided with aperipheral groove in which is nested a gasket 36 vfor effecting aliquid-tight seal between the confronting faces of stator 30 and basewall 27.

In order to lock stator 39 in a preselected vertical position, a ring 37is located and secured to the upper face of base wall 24 and securedthereto by suitable screws, the outer periphery of ring 37 beingprovided with regularly spaced notches 38. A latch element 39 isdisposed on the upper face of stator 32 and includes a radiallyextending arm 40 provided with a rear and an intermediate aperture andterminating at its outer end in a narrow depending leg 41 separablyengaging a notch 38. Latch 39 is releasably locked in position by meansof a headed bolt 42 having an axial shank registering with theintermediate aperture of latch 39, and a lower threaded shank engaging acorresponding tapped bore in stator 32. The rear aperture in latch 39 isslidably engaged by a pin 43 affixed to stator 32. Also releasablylocking stator 30 in a preselected position and inhibiting the looseningthereof and leakage therefrom is an adjustable nylon set screw 44engaging a corresponding tapped bore formed in the base wall 24 whichextends to the threaded section thereof.

Formed in the top face of the upper stator portion 33 is an outer lowerperipheral shoulder 46 separated from an inner raised shoulder 47 by avertical cylindrical wall, shoulder 47 being in turn separated from theupper edge of stator portion 33 by a vertical cylindrical wall todefine, with the shoulder 47, a recess which is engaged by a circulargasket 48 formed of any suitable resilient material.

A coupling member 49 includes a lower peripheral flange 50 terminatingin a depending lip 51 which abuts shoulder 46 and is aflixed thereto bybolts 52 registering with openings in flange 50 and engagingcorresponding tapped bores in stator 33. A conical wall 53 projectsupwardly from the inner edge of flange 50 and terminates in an upwardlydirected externally threaded tubular member 54. Coupling member 49 mayengage the internally threaded neck of a funnel-shaped hopper 12 or anysuitable pipe or fluid feed member.

The inner face of stator 30 is divided into a first upper or mainsection 56, an intermediate section 57 and a bottom section 58. Uppersection 56 occupies most of the inner surface of the stator and is ofconical configuration having a relatively small vertex anglesubstantially of the order illustrated. Formed in section 56 are aplurality of regularly circumferentially spaced, longitudinallyextending grooves 59 of arcuate cross-section which are separated byintervening teeth or ribs 60. It should be noted that the depth ofgrooves 59 decreases from the top to the bottom of stator 30, as doesthe height of the intervening teeth 60, the widths of which increase.

Intermediate stator surface section 57 is of horizontal annularconfiguration, the inner edge of which extends from the lower edge ofsurface section 56. Furthermore, the lower stator surface section 58 isof conical configuration having a relatively high vertex angle ascompared to that of the upper stator surface section 56. Regularlycircumferentially spaced, longitudinally and radially extending slots 63are formed in stator sections 57 and 58 and have arcuate bases 64. Slots63 delineate intervening teeth or ribs 65, the outer faces of whichdefine stator surface sections 57 and 58.

The mill rotor includes an assembly of an upper section 66, anintermediate core section 67 and a lower section 68, the assembly beingsuitably mounted on a vertical shaft 69. Shaft 69 is provided with alower portion which passes coaxially through column 18 registering withhearing members 21, and is connected by way of a coupling 79 to thedrive shaft of an electric motor 71 which is vertically supported onmount plate 14. Shaft 69 is locked in position by means of an integrallyformed collar 72 having a conical underface engaging upper bearing 21and a nut 73 which engages a threaded section of shaft 69 and abuts theunderface of lower bearing 21, whereby said shaft 69 is locked againstvertical movement. A suitable packing member 74 nests in collar 26 andengages shaft 69 to effect a liquid-tight seal.

Upper section 66 of the rotor includes a top portion 76 offrusto-conical configuration having an outer peripheral face ofsubstantially the same vertex angle and of slightly less diameter thanthe upper portion of the internal surface section 56 of the stator.Located on the top face of rotor section 66 are a plurality ofcircumferentially spaced, radially extending vanes 77 which define animpeller for driving the liquid or fluid fed into the mill to the outerperimeter where it flows through the comminuting zone. Vanes 77 projectfrom a centrally located collar 78 provided with a tapped axial borewhich is separated from a coaxial bore of similar diameter formed in thebottom of rotor portion 76 by an intermediate bore 79 of reducedcross-section.

Depending from the lower peripheral edge of rotor portion 76 and formedintegral therewith is a plurality of regularly circumferentially spaced,elongated vibrating elements or tines 80, each of which is ofsubstantially trapezoidal transverse cross-section, with an outwardlydirected base 81. The outer face of each tine delineates a conicalsurface which confronts and is closely spaced from the lower portion ofthe stator surface 56, and the adjacent sides of tines 80 convergeoutwardly to the spaces between the tines. Tines 80 increase incross-section from the tops to the bottoms thereof, and should resonateat a fundamental frequency in the sonic range and advantageously betweenabout twenty and thirty kilocycles per second and should preferably becapable of producing strong harmonics.

Formed in the peripheral face of rotor portion 76 is a plurality ofcircumferentially spaced longitudinally extending grooves 82 of arcuatecross-section, which grooves communicate and are colinear with thespaces between tines 80. The grooves 82 delineate intervening ribs orteeth 83 which advantageously differ in number from the teeth 60,preferably being one more or less.

Underlying rotor section 76 and surrounded by the tines 80 is thefrusto-conical core section 67 secured to the underface of the rotorsection 76 by connecting screws 86 engaging corresponding aligned tappedbores in rotor sections 67 and 76. The outer face of the rotor section67 is spaced inwardly from the inner faces of the tines 80, and hasformed therein circumferentially spaced longitudinally extending grooves87 which are in radial alignment with the axes of the adjacent tines 89.An axially extending bore 88 is formed in rotor section 67 which iscoaxial with and of greater diameter than the axial bore formed in therotor section 76.

Rotor section 68 includes a lower annular member 89 having an innerconical face surrounding and spaced from the peripheral surface ofcollar 26 and a flat bottom face parallel to and closely spaced from theupper face of base wall 23. The inner upper edge of the annular mem ber89 is bridged by a web 91 having a raised portion 92 which registerswith a corresponding recess formed in the underface of rotor portion 67.Rotor portions 67 and 68 are interconnected by a plurality of screws 94engaging aligned tapped bores formed therein. The peripheral face of theannular member 89 is spaced from the involute surface 29 and has acircumferential channel shaped groove 96 formed therein. Located in thegroove 96 are a plurality of spaced radially extending impellerdefiningvanes 97.

The upper face of annular member 89 includes an outer conical face 98which is parallel to and closely confronts the stator surface section 58and an inner upper annular face 99 which is parallel to and closelyconfronts the stator surface section 57. Radially extending slots 100'are formed in rotor faces 98 and 99, and are egularly peripherallyspaced therealong, the number of slots 100 being different than thenumber of slots 65, for example by one, and being many times greaterthan the number of slots 82.

The rotor is carried by shaft 69, as noted above, the lower axial boreformed in the rotor upper section 66 registering withthe upper section101 of shaft 69. The underface of rotor portion 76 rests on the upperface 102 of the rotor section 67'. The axial bores in the rotor sections67 and 68 engage the shaft section 103 and a key 104- registers withaligned keyways formed in the shaft section 103 and the confronting faceof the rotor bore. The rotor is locked against longitudinal movement inshaft 66 by a screw 106 extending through bore 79 and engaging a tappedbore in the shaft stub end 101. Feed screw 107, coaxial with the rotorand coupling member 54, is provided with a bottom threaded shankengaging the tapped coaxial bore in the upper end of shaft 69.

In the operation of the apparatus described above, the rotor is drivenby motor 71 at a high speed, for example 3600 r.p.m., and the mixture offluid and solid particulate material to be homogenized is introducedinto the hopper and drops or is screw-fed to the vanes 77. The mixtureis centrifugally driven to the peripheral zone and into the spacebetween the confronting faces of the rotor portion 76 and upper statorface 56. There the mixture is subjected to an intensive shearing actionand the solid phase reduced in particle size by shear impact andinterparticle attrition. As the mixture reaches the zone delineated bythe tines 80, it follows a highly tortuous and turbulent path about thetines 80 where the solid particles are highly reduced in size and byimpact, shear and interparticle friction, which action is greatlyenhanced by the intensive high frequency vibration of the tines 80. Thepresence of the vibrating tines 8t), excited by the rotation of therotor and the movement of the mixture, radically increases theefiiciency and effectiveness of the present apparatus. The mechanism andmode of operation is not completely understood although several theorieshave been proposed. As the mixture leaves the zone of the tines 80, itpasses through the zones delineated by the stator faces 57 and 58 andthe rotor faces 98 and 99 where further reduction and dispersion iseifected in the manner earlier set forth. The homogenized mixture isthen sucked by the pump including the impeller 97 and discharged throughthe pipe 30 As the material being processed is drawn downward to theregion of tines 80, the latter impel the material inwardly toward thecore 67 because of their inwardly converging faces, thereby reversingthe How of the material before it reaches stator faces 57, 58, whereatfurther reduction occurs.

As an example of a mill in accordance with the present invention, thereare provided 27 tines 80 each having a length of about 1%., a bottomoutside width of A a top outside width of and a depth of The rotor isformed of a type 316 stainless steel. During operation, the rotor wasdriven at 3600 r.p.m. and the measured frequency in the liquid at thedownstream or discharge end was registered between about 6 and 60kilocycles per second with a predominance in range of 20 to kilocyclesper second. In the absence of fluid, the magnitude of vibration wasconsiderably less with a greater frequency scatter.

An asphalt emulsion processed with the apparatus under the aboveconditions, upon an examination under an electron microscope, exhibitedan average particle size of 1.1 microns with a range between 0.7 and 4.5microns as compared with the same asphalt emulsion processed with apressure type homogenizer which had an average particle size of 4.5microns and a particle size range between 1.5 and 10.5 microns. Itshould be noted that the operating conditions of the apparatus may bealtered by adjusting the spacing between the stator and rotor byreleasing the latch 39 and turning stator 30 in base 22 as desired andthen locking latch 39. By reason of screw 44 being formed of an organicthermoplastic material, it reforms its end face to effect a liquid-tightseal. It may be repeatedly reemployed, as, in case of wear, thecontacting face of the screw 44 can be-in elfect-renewed by a half turnto reestablish its normal sealing and compression effect.

While there has been described and illustrated a preferred embodiment ofthe present invention, it is apparent that numerous alterations,omissions and additions may be made without departing from the spiritthereof.

I claim:

1. An improved comminuting apparatus, comprising a stator member havingan inner conical surface, and a rotor member coaxial with said statormember and including a core member having an outer conical surface and aplurality of circumferentially spaced longitudinally extending vibratingtines spaced from and around the surface of said core member, each ofsaid tines having one end thereof fixed to said core member and theother end thereof free, said tines having inner faces lying on a conicalsurface directly and unimpededly confronting said core outer surface todelineate therewith an uninterrupted peripheral zone bounded byconcurrently moving surfaces, outer faces lying on a conical surfaceconfronting and spaced from said stator inner surface and said coremember having formed in the peripheral face thereof longitudinal groovessubstantially registering with said tines.

2. A comminuting apparatus in accordance with claim 1, wherein saidtines have side faces converging inwardly toward said core grooves.

3. The comminuting apparatus of claim 1, wherein the inner conicalsurface of said stator member has circumferentially spacedlongitudinally extending grooves formed therein.

4. The comminuting apparatus of claim 3, wherein said tines and saidgrooves formed in said inner conical surface of said stator memberdiffer in number.

5. An improved comminuting apparatus comprising a base member includinga bottom wall and an upstanding peripheral wall, a stator member havingan inner conical surface, means securing said stator member to theperipheral Wall of said base member, a rotor member coaxial with saidstator member, said stator member being longitudinally adjustablerelative to said rotor member, said rotor member including a core memberhaving an outer conical surface and a plurality of circumferentiallyspaced longitudinally extending vibrating tines spaced from and aroundthe surface of said core member, each of said tines having one endthereof connected to said core mernber and the other end thereof free,said tines having outer faces lying on a conical surface confronting andspaced from the inner surface of said stator and inner faces lying on aconical surface directly and unimpededly confronting said core outersurface to delineate therewith an uninterrupted peripheral zone boundedby concurrently moving surfaces, and means rotatably supporting saidrotor member on said base member.

6. An improved comminuting apparatus, comprising a stator member havingan inner conical surface, and a rotor member coaxial with said statormember and including a core member having an outer conical surface and aplurality of circumferentially spaced longitudinally extending vibratingtines spaced from and around the surface of said core member, each ofsaid tines having one end thereof connected to said core member and theother end thereof free, said tines having outer faces lying on a conicalsurface confronting and spaced from the inner surface of said stator andinner faces lying on a conical surface directly and unimpededlyconfronting said core outer surfaces to delineate therewith anuninterrupted peripheral zone bounded by concurrently moving surfaces,the inner surface of said stator being provided with a second surface ofrevolution of greater vertex angle than said conical surface andextending outwardly from the base of said conical surface and a thirdsurface of revolution extending outwardly from said second surface ofrevolution and of smaller vertex angle relative thereto, said rotorbeing provided with sections below said core member which have outersurfaces corresponding to and confronting the second and third surfacesof revolution of said stator.

7. A comminuting apparatus in accordance with claim 6, wherein saidstator second and third surfaces and the confronting surfaces of saidrotor have longitudinally extending grooves formed therein.

References Cited in the file of this patent UNITED STATES PATENTS220,626 Leavitt Oct. 14, 1879 279,067 Wolf June 5, 1883 291,191 IttnerJan. 1, 1884 454,094 Vigreux June 16, 1891 2,383,437 Alexander Aug. 28,1945 2,657,021 Cottel et al. Oct. 27,1953 2,709,552 Le'cher May 31, 19552,757,909 Wayne Aug. 7, 1956 2,903,197 Willems Sept. 8, 1959 2.945,634Beck July 19, 1960 2,985,389 Willems May 23, 1961 FOREIGN PATENTS 805Sweden July 4, 1887 455,624 Great Britain Oct. 23, 1936 567,150 BelgiumMay 14, 1958

1. AN IMPROVED COMMINUTING APPARATUS, COMPRISING A STATOR MEMBER HAVINGAN INNER CONICAL SURFACE, AND A ROTOR MEMBER COAXIAL WITH SAID STATORMEMBER AND INCLUDING A CORE MEMBER HAVING AN OUTER CONICAL SURFACE AND APLURALITY OF CIRCUMFERENTIALLY SPACED LONGITUDINALLY EXTENDING VIBRATINGTINES SPACED FROM AND AROUND THE SURFACE OF SAID CORE MEMBER, EACH OFSAID TINES HAVING ONE END THEREOF FIXED TO SAID CORE MEMBER AND THEOTHER END THEREOF FREE, SAID TINES HAVING INNER FACES LYING ON A CONICALSURFACE DIRECTLY AND UNIMPEDEDLY CONFRONTING SAID CORE OUTER SURFACE TODELINEATE THEREWITH AN UNINTERRUPTED PERIPHERAL ZONE BOUNDED BYCONCURRENTLY MOVING SURFACES, OUTER FACES LYING ON A CONICAL SURFACECONFRONTING AND SPACED FROM SAID STATOR INNER SURFACE AND SAID COREMEMBER HAVING FORMED IN THE PERIPHERAL FACE THEREOF